TARGeted Intra-operative radioTherapy (TARGIT) for breast cancer - a randomised trial Jayant Vaidya,...
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Transcript of TARGeted Intra-operative radioTherapy (TARGIT) for breast cancer - a randomised trial Jayant Vaidya,...
TARGeted Intra-operative radioTherapy (TARGIT)
for breast cancer - a randomised trial
Jayant Vaidya, Michael Baum, Jeff Tobias, Joan Houghton,Mo Keshtgar,
Irving Taylor, Richard Sainsbury,
Derek D’Souza, S Morgan, M Metaxas, K Harte, A Sliski, E Thomson
Local treatment of breast cancer
Have the principles really changed?
Halsted’s Radical Mastectomy
Limited Surgery plus Radical Radiotherapy
Radiotherapy typically takes 6wks to deliver
Patients don’t like these 30 daily visits
Geography prevents many women from
receiving conservative breast surgery
Breast cancer = 1/3rd of RT work-load
Long waiting lists in many centres
Are there any problems with current approach?
The Solution
A novel radiotherapy technique that will accurately deliver all the necessary radiotherapy in ONE sitting
Treat only the index quadrant of breast
The RationaleWhole organ analysis of mastectomy specimens*
3-D analysis 63% harbour
occult cancer 80% of these
are in other quadrants
*Vaidya et al, Br. J. Cancer; 1996
The Rationale
but, in trials of conservative surgery:>90% recurrences occur in the index
quadrant
- whether radiotherapy is given or not
The occult cancers in other quadrants of the breast are probably not the cause of local recurrence.
Radiation to the index quadrant alone might be sufficient
Targeted Intra-operative Radiotherapy: (Targit)
A Novel Approach
The Technique
PRS400 (Intrabeam)A miniature electron generator and
accelerator
Accurately delivers radiotherapy from within the breastin about 25 minutes.
0 5 10 15 20
1
5
9
13
17
21
25
20 Gy at 2mm
1 Gy at 27mm
•Soft X-rays
•Small ‘very-high-dose’ region
•Quick attenuation (1/r3)-
– distance protects normal tissues
•Shielding is easy
Physical radiation dose
Applicator is inserted and purse string is tiedApplicator is inserted and purse string is tied
Rather than the complicated conformation of the source
to the target...
the target - the pliable breast tissue -
is conformed to the source
Targit with PRS
Estimated Biologically equivalent radiation dose (BED)
2mm e.g. breast 12 Gy 53 Gy
10mm e.g. skin
12 Gy 7 Gy
Distance from applicator
External
Boost /=10 /=1.5
121 Gy
21 Gy
1. To test the the TARGIT technique -its feasibility and safety
2. To test the approach of treating only the index
quadrant
Early operable breast cancer: <4cm in size
Phase I/II studyJuly 1998-Jan 2000
Wide Local excision + axillary surgery
Boost radiation with Photon Radio Surgery (PRS) intra-operatively
Whole breast radiotherapy post-op
Results – the pilot study
25 patients treated
With tumours ranging from 0.42 -4 cm
No major complicationsNo recurrences
Median follow up 30 m
Cosmetic results are good
ComplicationsOur 3rd patient had radionecrosis of skin
near the scar- skin was too close to the applicator
9 months
28 months
Cosmetic ResultsCosmetic Results
1) Photographs2) Patient’s own assessment of the
cosmetic result – appearance and texture:a) What would be your expected score
(out of 10)?b) What is the actual score (out of 10)
Satisfaction index = Actual / Expected
Cosmetic ResultsCosmetic Results
Satisfaction index (observed/expected)
Mean 95% CI
Appearance 1.2 (1.1-1.4)Texture 1.2 (1.0-1.4)
In only 4 out of the 25 patients in the pilot study, was the observed less than
expected.
Breast cancer - breast conserving therapy
RandomisationStudy Arm Control Arm
Wide local excision of primary tumour +
SNB/ axillary dissection + Targeted
Intraoperative Radiotherapy
(If histopathology is Lobular or EIC, add
5wks of postoperative radiotherapy)
Wide local excision of primary tumour
+SNB/ axillary dissection +6 wks of
Postoperative Radiotherapy
1st patient randomised on 29 March 2000
- 29 patients randomised until June 2001No complications in the IORT arm
1 wound infection in the post-op RT arm
Cosmetic appearance is good
No recurrences to date
Median follow up is 15 months
If proven, Targit could
Save up to 1/3rd of the workload of radiotherapy units world-wide
Allow women from remote areas to avail of breast conserving therapy